This is the exact Scifi equivalant of "M16 vs AK" "9mm vs .45 ACP". I just figured I'd point that out before I feed the trolls.
I give the win to Star Wars, by a wide margin. Disregarding Force vs. Q, the Empire can simply crush the life out of anything it chooses to. Even disregarding the Death Star and other Imperial superweapons, the Empire has a massive edge.
Even if the Federation switched to a war footing, it would still lose. The reason is that they prefer small numbers of large ships. Up until ST 2.0, I never saw a ship fire weapons in salvos, have extensive backup weapons, and I've yet to see fighter, frigate, or destroyer-class ships used in concert with capital-class ships.
The SW universe, on the other hand, recognizes that warfare in space will probably resemble naval warfare in WWII, and added in various sizes and purposes of ships. Sure, the enterprise, with its super-powerful, super-accurate main phaser can shred TIE-Fighters, but the fact remains that all it would take is for three or four TIE bombers to get through, and the Enterprise is fucked. Not to mention that other types of TIEs could be strafing engines, weapons, sensors, etc.